1. Field of the Invention
The present invention relates to an ink use amount evaluation apparatus, an ink use amount evaluation method and an inkjet apparatus, and more particularly to image signal processing technology suitable for calculating a prediction of an ink use amount when performing image formation (printing) by means of a liquid ejection head based on an inkjet system, and judging whether or not image formation quality is to be affected.
2. Description of the Related Art
When high-density printing is carried out on printing paper using an inkjet printer, the water content in the ink breaks hydrogen bonds between the pulp fibers of the paper, the pulp fibers then expand, and undulation (wrinkling, distortion) of the paper, known as cockling, is produced (see Paragraph 0010 in Japanese Patent Application Publication No. 2003-039652). When paper deformation of this kind occurs, problems occur in that the ink deposition accuracy declines and the paper touches the inkjet head.
Japanese Patent Application Publication No. 2003-039652 proposes a composition in which, in order to prevent decline in print quality, such as paper conveyance errors or decline in image quality, and the like, due to cockling, a total ink use amount is determined by rasterizing input image data and if the determined total ink use amount is greater than a threshold value, then the total ink amount is reduced by using a table (mask data) which causes the total ink amount to become not greater than the threshold value.
Japanese Patent Application Publication No. 2003-039652 describes a method in which the total ink amount is determined from image data for printing by calculating the total ink amount directly from raster data of the image (paragraph 0018), and the method uses fixed conditions for the conversion relationship from the raster data to the total ink amount. However, in an inkjet printer having an adjustment mechanism for tone adjustment and density non-uniformity adjustment (non-uniformity correction), the relationship between the image data and the total ink amount is not uniform and varies depending on the image adjustment conditions which are determined by the tone adjustment and the density non-uniformity adjustment. Consequently, the total ink amount used in image formation increases or decreases depending on the image adjustment conditions, even for the same image data, and hence an accurate ink amount cannot be ascertained with the technology in Japanese Patent Application Publication No. 2003-039652.